Governing means, including a fluid pressure responsive member and a control device therefor



Aug. 14, 1951 R J 2,564,263

GOVERNING MEANS INCLUDING A FLUID PRESSURE REsPoNsIvE MEMBER AND ACONTROL DEVICE THEREFOR Filed Sept. 10, 1946 Patented Aug. 14, 1951GOVERNING MEANS, INCLUDING A FLUID PRESSURE RESPONSIVE MEMBER AND ACONTROL DEVICE THEREFOR Richard Joseph Ifield, Birmingham, England, as-

signor to Joseph Lucas Limited, Birmingham,

England Application September 10, 1946, Serial No. 696,012 In GreatBritain September 13, 1945 1 Claim.

This invention relates to governing means for use with variable deliverypumps and of the kind having fluid operable means for varying the pumpoutput. More particularly the invention is required for pumps of theswash plate type used for supplying liquid fuel to internal combustionprime movers. When the system containing such a pump is provided with amanually operable or other throttle valve for varying the rate ofdelivery of liquid in accordance with variations of demand, it isdesirable to vary correspondingly the rate of delivery from the pump,and the object of the present invention is to enable this requirement tobe satisfied automatically in a simple and convenient manner.

The accompanying drawing is a diagrammatic sectional side viewillustrating the invention applied to a variable delivery pumpof theswashplate type for supplying liquid fuel to an internal combustionprime mover.

The liquid fuel pump shown in the drawing comprises a rotary body part aarranged in a casing b and having formed around its axis a plurality ofbores in each of which is arranged a reciprocatory plunger. The bodypart a is adapted to be driven in any convenient manner by the primemover (not shown) to be supplied with liquid fuel from the pump. Duringrotation of the body part a the plungers are moved in one direction byan angularly movable swash plate and in the opposite direction bysprings, the latter being situated within the bores in the body part,and serving to hold an end face of the body part in contact with a flatseating g in the casing 17 The plungers, swash plate, and associatedparts of the pump are well known, and are not shown in the drawing. Theseating g is formed with port h communicating with a liquid fuel inletpassage i and with another port 9' communicating with a liquid fueldelivery passage k In one end of the casing b is formed a cylinder mhaving closed ends. Within the cylinder m is arranged a piston o loadedby a spring 11 and extending from one side of the piston and through abore in the casing b at the inner end of the cylinder is a rod q thelatter being connected to the swash plate of the pump so that movementof the piston serves to adjust the position of the swash plate forvarying the rate of delivery of the pump. The inner end of the cylinderm is in free communication with the delivery passage k through a passage1 in the casing b and also communicates with the outer end of thecylinder through a restricted passage the spring 11 being arrangedbetween the outer end of the cylinder and'the adjacent side of thepiston 0 The outer end of the cylinder m is provided with avalve-controlled vent t Normally the pressures acting on the two sidesof the piston o are balanced, but when a state of unbalance is createdby escape of liquid from the outer end of the cylinder through the ventt the fluid pressure acting on the side of the piston remote from thevent will cause the piston to move in the direction for adjusting theobliquity of the swash plate of the pump, and thereby reducing the pumpoutput. i I

In a hollow body u is arranged a vent valve '0 and a seating w withwhich the valve can co-operate for controlling the vent t the valvebeing carried by a lever m which is loaded by a spring y At one side ofthe seating w the hollow body u is adapted for connection to the vent tand at the other side of the seating the hollow body is in communicationwith a drain 2 the arrangement being such that on opening the valve 0fluid can escape from the adjacent end of the cylinder m and so enablethe pressure in the other end of the cylinder to move the piston o inthe desired manner for adjusting the swash plate of the pump.

Arranged between the pump and the discharge end of the delivery passagek is a throttle valve 3 of any convenient form, this being operablemanually or otherwise for varying the rate of discharge of liquid inresponse to variations of demand. The throttle valve 3 may convenientlyconsist as shown of a plug which has a tapered end extending into thedelivery passage and which is movable axially through the medium of rackand pinion mechanism (not shown).

The hollow body u has combined with it a chamber 6 which is divided intotwo compartments by a flexible diaphragm l (or an equivalent piston),this diaphragm being adapted to actuate through the medium of a stem 8the lever .73 carrying the vent valve 0 The two compartments of thechamber 6 are connected by passages 9 to the delivery passage k at theinlet and outlet sides respectively of the throttle valve 3 so that thediaphragm l is responsive to the pressure diiierence across the throttlevalve. With increase of this pressure difference, consequent uponrestriction of flow past the throttle valve the diaphragm 1 causes thevent valve 0 to open and so enables the pump-controlling piston 0 toefiect a corresponding diminution of the rate of delivery of liquid bythe pump. Similarly when the throttle valve 3 is moved to increase theflow past it, thus causing a drop in the pressure difference abovementioned, th vent valve 3 closes, and the pump-controlling piston o isthen moved in the opposite direction by its spring 11 for increasing thepump output.

The hollow body u is divided into two chambers II], II by a diaphragml2, and an intermediate part of the lever 37 carrying the vent valve 1:is secured to this diaphragm which serves as a fulcrum for the lever. Inthe chamber I is arranged a flexible capsule [3 which is supported atits opposite ends respectively by the end of the lever 9: remote fromthe vent valve 12 and by an adjustable abutment M. The chamber [0communicates in any convenient manner with the outer atmosphere, and thecapsule I3 is responsive to atmospheric pressure. The vent valve 12 issituated in the other chamber II, and the adjacent end of the lever .ris loaded by the spring g The chamber II also contains one end of thestem 8 through which the diaphragm l in the chamber 6 acts on the leverx By this invention 1 am able to correlate the pump output with theextent of opening of the throttle valve in a simple and satisfactorymanner. The invention is not, however, restricted to the examplesdescribed as constructional details may be modified to suit differentrequirements. Also the invention may be applied to pumps other thanthose of the swash plate type.

Having thus described my invention. what I claim as new and desire tosecure by Letters Patent is:

Governing means of the kind specified, having in combination a mainpassage for fluid under pressure, a throttle valve for controlling theflow of pressure fluid through said main passage, a fluid pressureresponsive member, a chamber containing said member, another passage foradmitting an unrestricted supply of pressure fluid to said chamber atone side of said member from said main passage at the inlet side of saidthrottle valve, a restricted passage through which pressure fluid canflow to said chamber at the other side of said member from said mainpassage at the inlet side of said throttle valve, a vent valve forreleasing from said chamber pressure fluid admitted thereto through saidrestricted passage, a spring loaded lever carrying said vent valve, ahollow body containing said lever and provided with a seating for saidvent valve, a diaphragm dividing said body into two chambers and servingas a fulcrum to which an intermediate part of said lever is attached, abarometric capsule arranged in one of said chambers and acting on saidlever, a second pressure-fluid responsive member, a housing associatedwith said body and containing said second member, passages for admittingpressure fluid to said housing at opposite sides of said second memberfrom said main passage at opposite sides respectively of said throttlevalve so that said second member is responsive to the difference ofpressure between the inlet and outlet sides of said throttle valve, anda stem through which said second member acts on said lever.

RICHARD JOSEPH IFTELD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,992,048 Temple Feb. 19, 19352,020,847 Mitereff Nov. 12, 1935 2,220,180 Spitzglass Nov. 5, 19402,286,188 MacLean June 16, 1942 2,403,371 Ifield et al July 2, 19462,407,013 Ifield Sept. 3, 1946

